On this picture one can see the spool with the copper-beryllium tape (it is the most expensive part - the actual antenna element), the plastic shaft extension of the stepper motor with the sprocket and the back of the UHF connector.

I ordered my antenna with N type connector but SteppiR Antennas shipped me a unit  with UHF type connector by mistake. I didn't want to send the EHU back for replacement so I decided to change the connector  myself.